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Re: [Xen-devel] [PATCH] xen: ioapic: avoid gcc 4.6 warnings about uninitialised variables

On Mon, 2011-05-16 at 13:04 +0100, Ian Campbell wrote:
> On Mon, 2011-05-16 at 12:29 +0100, Jan Beulich wrote:
> > >>> On 09.05.11 at 12:43, Ian Campbell <ian.campbell@xxxxxxxxxx> wrote:
> > > # HG changeset patch
> > > # User Ian Campbell <ian.campbell@xxxxxxxxxx>
> > > # Date 1304937815 -3600
> > > # Node ID 35abcbcdf8bcabab6e0bbd929f69b613e167edfd
> > > # Parent  4b0692880dfa557d4e1537c7a58c412c1286a416
> > > xen: ioapic: avoid gcc 4.6 warnings about uninitialised variables
> >
> > Seems like this got lost,

Keir has now applied it to xen-unstable.hg as 23371:87084ca76c9c.

Ian.

>  but it really doesn't only fix a compiler
> > warning, because (not mentioned in the description) ...
> [....]
> > > @@ -229,11 +265,7 @@ int restore_IO_APIC_setup(struct IO_APIC
> > >              return -ENOMEM;
> > >
> > >          for (pin = 0; pin < nr_ioapic_registers[apic]; pin++)
> > > -            entry = ioapic_entries[apic][pin];
> > > -            spin_lock_irqsave(&ioapic_lock, flags);
> > > -            __io_apic_write(apic, 0x11+2*pin, *(((int *)&entry)+1));
> > > -            __io_apic_write(apic, 0x10+2*pin, *(((int *)&entry)+0));
> > > -            spin_unlock_irqrestore(&ioapic_lock, flags);
> > > +         ioapic_write_entry(apic, pin, 1, ioapic_entries[apic][pin]);
> >
> > ... this for's (intended) body was lacking braces. Hence this
> > definitely is also a 4.1/4.0 back-porting candidate.
> 
> Oh wow, I didn't notice that, hence it was not mentioned in the commit
> message.
> 
> Actually, that could explain the warnings too since entry might really
> not be initialised in this erroneous code, e.g. if
> nr_ioapic_registers[apic] == 0.
> 
> Ian.
> 
> >
> > Jan
> >
> > >      }
> > >
> > >      return 0;
> > > @@ -338,18 +370,10 @@ static void eoi_IO_APIC_irq(unsigned int
> > >  #define clear_IO_APIC_pin_raw(a,p) __clear_IO_APIC_pin(a,p,1)
> > >  static void __clear_IO_APIC_pin(unsigned int apic, unsigned int pin, int
> > > raw)
> > >  {
> > > -    unsigned int (*read)(unsigned int, unsigned int)
> > > -        = raw ? __io_apic_read : io_apic_read;
> > > -    void (*write)(unsigned int, unsigned int, unsigned int)
> > > -        = raw ? __io_apic_write : io_apic_write;
> > >      struct IO_APIC_route_entry entry;
> > > -    unsigned long flags;
> > > -
> > > +
> > >      /* Check delivery_mode to be sure we're not clearing an SMI pin */
> > > -    spin_lock_irqsave(&ioapic_lock, flags);
> > > -    *(((int*)&entry) + 0) = (*read)(apic, 0x10 + 2 * pin);
> > > -    *(((int*)&entry) + 1) = (*read)(apic, 0x11 + 2 * pin);
> > > -    spin_unlock_irqrestore(&ioapic_lock, flags);
> > > +    entry = ioapic_read_entry(apic, pin, raw);
> > >      if (entry.delivery_mode == dest_SMI)
> > >          return;
> > >
> > > @@ -358,10 +382,7 @@ static void __clear_IO_APIC_pin(unsigned
> > >       */
> > >      memset(&entry, 0, sizeof(entry));
> > >      entry.mask = 1;
> > > -    spin_lock_irqsave(&ioapic_lock, flags);
> > > -    (*write)(apic, 0x10 + 2 * pin, *(((int *)&entry) + 0));
> > > -    (*write)(apic, 0x11 + 2 * pin, *(((int *)&entry) + 1));
> > > -    spin_unlock_irqrestore(&ioapic_lock, flags);
> > > +    ioapic_write_entry(apic, pin, raw, entry);
> > >  }
> > >
> > >  static void clear_IO_APIC (void)
> > > @@ -990,11 +1011,10 @@ static void __init setup_IO_APIC_irqs(vo
> > >              SET_DEST(entry.dest.dest32, entry.dest.logical.logical_dest,
> > >                       cpu_mask_to_apicid(&cfg->cpu_mask));
> > >              spin_lock_irqsave(&ioapic_lock, flags);
> > > -            io_apic_write(apic, 0x11+2*pin, *(((int *)&entry)+1));
> > > -            io_apic_write(apic, 0x10+2*pin, *(((int *)&entry)+0));
> > > +            __ioapic_write_entry(apic, pin, 0, entry);
> > >              set_native_irq_info(irq, TARGET_CPUS);
> > >              spin_unlock_irqrestore(&ioapic_lock, flags);
> > > -     }
> > > +        }
> > >      }
> > >
> > >      if (!first_notcon)
> > > @@ -1007,7 +1027,6 @@ static void __init setup_IO_APIC_irqs(vo
> > >  static void __init setup_ExtINT_IRQ0_pin(unsigned int apic, unsigned int
> > > pin, int vector)
> > >  {
> > >      struct IO_APIC_route_entry entry;
> > > -    unsigned long flags;
> > >
> > >      memset(&entry,0,sizeof(entry));
> > >
> > > @@ -1038,10 +1057,7 @@ static void __init setup_ExtINT_IRQ0_pin
> > >      /*
> > >       * Add it to the IO-APIC irq-routing table:
> > >       */
> > > -    spin_lock_irqsave(&ioapic_lock, flags);
> > > -    io_apic_write(apic, 0x11+2*pin, *(((int *)&entry)+1));
> > > -    io_apic_write(apic, 0x10+2*pin, *(((int *)&entry)+0));
> > > -    spin_unlock_irqrestore(&ioapic_lock, flags);
> > > +    ioapic_write_entry(apic, pin, 0, entry);
> > >
> > >      enable_8259A_irq(0);
> > >  }
> > > @@ -1148,10 +1164,7 @@ static void /*__init*/ __print_IO_APIC(v
> > >       for (i = 0; i <= reg_01.bits.entries; i++) {
> > >              struct IO_APIC_route_entry entry;
> > >
> > > -            spin_lock_irqsave(&ioapic_lock, flags);
> > > -            *(((int *)&entry)+0) = io_apic_read(apic, 0x10+i*2);
> > > -            *(((int *)&entry)+1) = io_apic_read(apic, 0x11+i*2);
> > > -            spin_unlock_irqrestore(&ioapic_lock, flags);
> > > +            entry = ioapic_read_entry(apic, i, 0);
> > >
> > >              printk(KERN_DEBUG " %02x %03X %02X  ",
> > >                     i,
> > > @@ -1212,7 +1225,6 @@ static void __init enable_IO_APIC(void)
> > >  {
> > >      int i8259_apic, i8259_pin;
> > >      int i, apic;
> > > -    unsigned long flags;
> > >
> > >      /* Initialise dynamic irq_2_pin free list. */
> > >      irq_2_pin = xmalloc_array(struct irq_pin_list, PIN_MAP_SIZE);
> > > @@ -1227,12 +1239,7 @@ static void __init enable_IO_APIC(void)
> > >          int pin;
> > >          /* See if any of the pins is in ExtINT mode */
> > >          for (pin = 0; pin < nr_ioapic_registers[apic]; pin++) {
> > > -            struct IO_APIC_route_entry entry;
> > > -            spin_lock_irqsave(&ioapic_lock, flags);
> > > -            *(((int *)&entry) + 0) = io_apic_read(apic, 0x10 + 2 * pin);
> > > -            *(((int *)&entry) + 1) = io_apic_read(apic, 0x11 + 2 * pin);
> > > -            spin_unlock_irqrestore(&ioapic_lock, flags);
> > > -
> > > +            struct IO_APIC_route_entry entry = ioapic_read_entry(apic, 
> > > pin,
> > > 0);
> > >
> > >              /* If the interrupt line is enabled and in ExtInt mode
> > >               * I have found the pin where the i8259 is connected.
> > > @@ -1288,7 +1295,6 @@ void disable_IO_APIC(void)
> > >       */
> > >      if (ioapic_i8259.pin != -1) {
> > >          struct IO_APIC_route_entry entry;
> > > -        unsigned long flags;
> > >
> > >          memset(&entry, 0, sizeof(entry));
> > >          entry.mask            = 0; /* Enabled */
> > > @@ -1305,12 +1311,7 @@ void disable_IO_APIC(void)
> > >          /*
> > >           * Add it to the IO-APIC irq-routing table:
> > >           */
> > > -        spin_lock_irqsave(&ioapic_lock, flags);
> > > -        io_apic_write(ioapic_i8259.apic, 0x11+2*ioapic_i8259.pin,
> > > -                      *(((int *)&entry)+1));
> > > -        io_apic_write(ioapic_i8259.apic, 0x10+2*ioapic_i8259.pin,
> > > -                      *(((int *)&entry)+0));
> > > -        spin_unlock_irqrestore(&ioapic_lock, flags);
> > > +        ioapic_write_entry(ioapic_i8259.apic, ioapic_i8259.pin, 0, 
> > > entry);
> > >      }
> > >      disconnect_bsp_APIC(ioapic_i8259.pin != -1);
> > >  }
> > > @@ -1838,17 +1839,13 @@ static void __init unlock_ExtINT_logic(v
> > >      int apic, pin, i;
> > >      struct IO_APIC_route_entry entry0, entry1;
> > >      unsigned char save_control, save_freq_select;
> > > -    unsigned long flags;
> > >
> > >      pin = find_isa_irq_pin(8, mp_INT);
> > >      apic = find_isa_irq_apic(8, mp_INT);
> > >      if (pin == -1)
> > >          return;
> > >
> > > -    spin_lock_irqsave(&ioapic_lock, flags);
> > > -    *(((int *)&entry0) + 1) = io_apic_read(apic, 0x11 + 2 * pin);
> > > -    *(((int *)&entry0) + 0) = io_apic_read(apic, 0x10 + 2 * pin);
> > > -    spin_unlock_irqrestore(&ioapic_lock, flags);
> > > +    entry0 = ioapic_read_entry(apic, pin, 0);
> > >      clear_IO_APIC_pin(apic, pin);
> > >
> > >      memset(&entry1, 0, sizeof(entry1));
> > > @@ -1862,10 +1859,7 @@ static void __init unlock_ExtINT_logic(v
> > >      entry1.trigger = 0;
> > >      entry1.vector = 0;
> > >
> > > -    spin_lock_irqsave(&ioapic_lock, flags);
> > > -    io_apic_write(apic, 0x11 + 2 * pin, *(((int *)&entry1) + 1));
> > > -    io_apic_write(apic, 0x10 + 2 * pin, *(((int *)&entry1) + 0));
> > > -    spin_unlock_irqrestore(&ioapic_lock, flags);
> > > +    ioapic_write_entry(apic, pin, 0, entry1);
> > >
> > >      save_control = CMOS_READ(RTC_CONTROL);
> > >      save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
> > > @@ -1884,10 +1878,7 @@ static void __init unlock_ExtINT_logic(v
> > >      CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
> > >      clear_IO_APIC_pin(apic, pin);
> > >
> > > -    spin_lock_irqsave(&ioapic_lock, flags);
> > > -    io_apic_write(apic, 0x11 + 2 * pin, *(((int *)&entry0) + 1));
> > > -    io_apic_write(apic, 0x10 + 2 * pin, *(((int *)&entry0) + 0));
> > > -    spin_unlock_irqrestore(&ioapic_lock, flags);
> > > +    ioapic_write_entry(apic, pin, 0, entry0);
> > >  }
> > >
> > >  /*
> > > @@ -2262,8 +2253,7 @@ int io_apic_set_pci_routing (int ioapic,
> > >          disable_8259A_irq(irq);
> > >
> > >      spin_lock_irqsave(&ioapic_lock, flags);
> > > -    io_apic_write(ioapic, 0x11+2*pin, *(((int *)&entry)+1));
> > > -    io_apic_write(ioapic, 0x10+2*pin, *(((int *)&entry)+0));
> > > +    __ioapic_write_entry(ioapic, pin, 0, entry);
> > >      set_native_irq_info(irq, TARGET_CPUS);
> > >      spin_unlock(&ioapic_lock);
> > >
> > >
> > > _______________________________________________
> > > Xen-devel mailing list
> > > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > > http://lists.xensource.com/xen-devel
> >
> >
> 
> 
> 
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> http://lists.xensource.com/xen-devel



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